Centrifugal discharge filter seals

ABSTRACT

A rotary filter unit has a pressure casing in which is rotatably mounted a shaft having filter means thereon. Both ends of the shaft are rotatably supported and are surrounded by inflatable sealing means which may be selectively inflated and deflated. When inflated, the sealing means engage the periphery of the shaft to provide a secure seal between the interior of the casing and the exterior thereof. When deflated, the inflatable sealing means are spaced from the periphery of the shaft.

United States Patent Inventor Ernie G. Seggebruch East Moline, Ill. Appl. No. 3,365 Filed Jan. 16, 1970 Patented Sept. 28, 1971 Assignee Ametek, Inc.

New York, N.Y.

CENTRIFUGAL DISCHARGE FILTER SEALS 4 Claims, 2 Drawing Figs.

US. Cl 210/331, 277/ 34 Int. Cl 801d 29/02 Field of Search 210/360,

[56] References Cited I UNITED STATES PATENTS 2,606,046 8/1952 Bonner et al. 277/34 X 2,678,133 5/1954 Thayer etal.... 210/360 X 2,863,681 12/1958 Robbins 277/34 Primary Examiner-J. L. DeCesare Attorne'y-Smythe & Moore ABSTRACT: A rotary filter unit has a pressure casing in which is rotatably mounted a shaft having filter means thereon. Both ends of the shaft are rotatably supported and are surrounded by inflatable sealing means which may be selectively inflated and deflated. When inflated, the sealing means engage the periphery of the shaft to provide a secure seal between the interior of the casing and the exterior thereof. When deflated, the inflatable sealing means are spaced from the periphery of the shaft.

CENTRIFUGAL DISCHARGE FILTER SEALS One form of a rotary filter comprises a pressure casing having a rotatable shaft journaled therein in an upright or vertical position. A plurality of axially spaced filter leaves are mounted along the shaft within the casing. One end of the shaft generally protrudes from the casing and is connected to a power drive unit. This end of the shaft if usually provided with a suitable seal or packing in order to seal off the interior of the casing. The other end of the shaft, which may be rotatably supported within the casing, is similarly provided with a seal or packing since the shaft is hollow and communicates with a drain tube leading to the exterior of the casing. While a wide variety of seals has been devised for rotating shafts, it has been found that it is not necessary that the shaft be sealed at all times. It is preferred that the shaft be sealed during the filtration process, but it is not necessary that the shaft be sealed after filtration has been completed and the shaft is being rotated to centrifugally discharge the cake from the filter leaves.

1 One of the objects of the present invention is to provide an improved centrifugal discharge filter seal.

Another of the objects of the present invention is to provide an inflatable seal for the rotary shaft of a centrifugal discharge filter.

According to one aspect of the present invention, a rotary centrifugal discharge filter unit may comprise a pressure casing. A shaft is rotatably journaled in the casing and has one end extending outwardly thereof. Suitable filter means, such as a plurality of filter leaves, are mounted upon the shaft within the casing. Mounted on a suitable structure on the easing are inflatable means for sealingly engaging the shaft adjacent the end extending from the casing. The inflatable means extend circumferentially around the shaft and may be selectively inflated and deflated.

Other objects, advantages and features of the present invention will be apparent from the accompanying description and drawings, which are merely exemplary.

In the drawings:

FIG. 1 is a vertical sectional view along the rotary axis of a rotary centrifugal discharge filter incorporating the present invention; and

FIG. 2 is a view similar to FIG. 1 but in enlarged scale and the central portion of the shaft being removed to illustrate the inflatable sealing means on both ends of the shaft in greater detail.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views, a specific embodiment of the present invention will be described in detail.

A rotary filter unit incorporating the present invention is indicated generally at in FIG. 1 and comprises a vertically upstanding pressure tank or casing 11 having a conical bottom 12 and a discharge opening 13 at the apex of the bottom with a dump valve 14 being provided in the discharge opening.

The upper end of the tank is closed by a topplate 15 having a central opening 16 therein within which is secured a tubular hub 17. Concentric with hub 17 is a second hub 18 which is also mounted on the top face of the plate 15 and is provided at its upper end with a bearing assembly indicated generally at 19 within which is journaled a tapered end 20 of a shaft 21. The

' bearing assembly may flexibly suspend the rotating parts so that the rotating parts will spin above the critical speed or natural frequency of the mounting. The flexible suspension may be accomplished in any suitable manner such as by flexible member 19A. Cup-shaped means 198 cooperates with member 19C. The upper end of the tapered end 20 is threaded and has a nut 22 attached thereto to retain the shaft 21 in vertical position.

The shaft 21 is spaced from the inner surface of the boss 17 and carries a seal or packing 23 which rides in a groove formed in the upper end of the hub 17. The lower portion of the shaft 21 is hollow as indicated as 24, and there are a plurality of circular filter discs 25 axially spaced along this hollow portion of the shaft. The filter discs 25 are mounted in a manner known in the art and communicate with the interior of shaft 21 through corresponding openings 26.

The lower end of shaft 21 is positioned within a cup-shaped member 27 which is mounted at the central vertical axis of the tank by means of a suitable structure indicated at 28. The lower end of shaft 21 is opened to the interior of the member 27 and communicates to the exterior of tank 11 through a conduit 29.

Also mounted on the tapered upper end 20 of the shaft 21 is a pulley 30 which is drivingly connected with a drive motor 31 by means of driving belts 32.

According to the present invention, the inflatable seals are indicated at 33 and 34 and are mounted in he hub 17 and cupshaped member 27, respectively, as can be seen in greater detail in FIG. 2. The inflatable seals 33 and 34 are annular in shape and encircle the respective portions of the shaft 21. Tubes 35 and 36 connect the inflatable seals 33 and 34 with suitable inflating and deflated means which may comprise a pump structure having a suitable control circuit. The seals may be inflated with compressed air or other gases as may be suitable for the particular operation of the filter units. The inflatable seals may be made of a suitable flexible and resilient material, for example, such as fabric reinforced neoprene.

During the filtration process, the rotatable shaft and the filter discs mounted thereon will be stationary and the inflatable seals 33 and 34 will be inflated so as to provide a seal between the interior of the pressure tank 11 and the exterior of the filter unit. Upon completion of the filtration process, the seals are then deflated and the shaft and filter discs rotated so as to discharge the filter cake which has been formed on the several filter discs. The discharge cake then accumulates in the conical bottom 22 of the tank and is subsequently discharged through the dump valve 14.

Thus, it can be seen that the present invention has disclosed a sealing arrangement for rotary filter units which is selectively operable operable between sealing and nonsealing conditions.

What is claimed is:

1. In a rotary centrifugal discharge filter, the combination including a pressure casing, shaft casing, means for rotatably and flexibly journaling said shaft means adjacent one end in said casing, filter means mounted on said shaft, remotely operable inflatable sealing means extending circumferentially around said shaft and means for selectively inflating and deflating said sealing means around said shaft means adjacent said one end thereof.

2. In a filter as claimed in claim 1 and comprising a hub on said casing extending externally thereof and surrounding said shaft, said inflatable sealing means being mounted within said hub.

3. In a filter as claimed in claim 1 and means within said casing for rotatably supporting the other end of said shaft, and second inflatable means in said rotatable supporting means for sealingly said shaft adjacent the other end thereof.

4. In a filter as claimed in claim 1 wherein said inflatable means is spaced from the periphery of said shaft when in the deflated condition.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 3,608,731 Dated September 28, l9Yl Invent fl Ernie G. Seg ebruch It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shovm below:

Column 1, line 56, "topplete" should be --top-plate--. Column 2, line 21, "he' should be --the--; Column 2,

line 26, "deflated" should be --deflating--; Column 2, line 4 delete "operable" (second occurrence); Column 2, line 49, "casin (second occurrence) should be --means--; Column 2, line %3, after "sealingly" insert --engaging--.

Signed and sealed this 9th day of May 1972.

(SEAL) Attest EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents DRM pomso HO'SQ] USCOMM-DC wave-Pea Q U S, EQVEHNMENT PRlNTlNG OFFICE! 19. 0-38-3! 

1. In a rotary centrifugal discharge filter, the combination including a pressure casing, shaft means, means for rotatably and flexibly journaling said shaft means adjacent one end in said casing, filter means mounted on said shaft, remotely operable inflatable sealing means extending circumferentially around said shaft and means for selectively inflating and deflating said sealing means around said shaft means adjacent said one end thereof.
 2. In a filter as claimed in claim 1 and comprising a hub on said casing extending externally thereof and surrounding said shaft, said inflatable sealing means being mounted within said hub.
 3. In a filter as claimed in claim 1 and means within said casing for rotatably supporting the other end of said shaft, and second inflatable means in said rotatable supporTing means for sealingly said shaft adjacent the other end thereof.
 4. In a filter as claimed in claim 1 wherein said inflatable means is spaced from the periphery of said shaft when in the deflated condition. 